Method of coking heavy petroleum residues or the like



Jan. 30, 1934. c. w. ANDREWS 'Er AL 1,944,872

'METHOD OF COKING HEAVY PETROLEUM. RESIDUES 0R THE LIKE Filed Des. 11,192s s sheets-sheet 1 Jan'. 30, 1934. c. w. ANDREWS ET AL 1,944,872

METHOD 0F COKING- HEAVY PETROLEUM RESIDUES 0R THE LIKE Filed Dec. 11,1929 s sheets-sheet 2 y @Mw/21@ Jam 30, 1934 c. w. ANDREWS r-:r AL1,944,872

METHOD OF COKING HEAVY .PETROLEUM RESIDUES 0R THE LIKE W l E@ w w 7 I lha l UD I D L 3% n u n v" D #wr ,b n n/-Jwu j h w D I n 'n ig @D D l D%W D QU I n n n l? l n MHH {B-@YQ (n n i D n n n `Patented Jan. 30,1934l STATES PATENT OFFIC METHOD OF COKING HEAVY PETROLEUM RESIDUES ORTHE LIKE Application December v1li, 1929 Serial No. 413,207

3 claims. (ci. 2oz-i7) hydrocarbons Ain liquid form.

In our prior Patent No. 1,805,711 granted May 19, 1931, we have shown 'aform of oven heated from below by flues under the sole of the oven,

. which oven is adapted for the coking of heavy residues of thischaracter, the volatile constituents of the residues being driven offand. collected as oils of lower viscosity than the residue beingtreated. This type of'chamber, however, re-

quires that except for the sensible heat of the feed, all of the heatfor the reaction be lpassed through the floor of the oven and alsothrough the layer of coked material which forms on the oven floor. Thismethod of applying the heat gives a very desirable metallurgical coke,but is comparatively slow.

It is an object of this present invention to provide a new and improvedmethod whereby the heat, or 'a large portion of the heat, necessary forcarrying on the coking operation may be supplied internally of thecoking chamber.

It is an additional object to provide a' method wherein this heat may beprovided by means of partial combustion of the material within thechamber.

It is a further object to provide a method in which internal heat may besupplied in whole or in part by products of a combustion carried onexternally of the chamber and with, or without,- secondary combustion inthe chamber.

It is an additional object to provide a method whereby the internal heatnecessary for coking may be provided in the chamber with, or without,the application of additional heat through the i'loor or sole of theoven.

It is also an object to provide a method in which the residue beingtreated and the oxygen or oxygen-containing gas are intimately mixed soas to produce an'effecti've combustion.

It is an additional object to provide a method of this character inwhich additional heat may be supplied -if desired through the iioor ofthe oven in which the operation `takes place.'

It is also an object to provide a method in which the waste heat of theprocess may be utilized for preheating the incoming carbonaceousmaterial and air.

It is a further object to provide a chamber in which the coke iscontinuously formedand continuously removed.

Other and furtherl objects will appear as the description proceeds.

We have shown somewhat diagrammatically in the accompanying drawings,certain preferred embodiments of an apparatus adapted for carrying outour improved method.

In the drawings- Figure 1 is` alongitudinal section of the apparatus; c-

Figure 2 is a transverse section of the ap paratus;

Figure 3 is a plan View of the apparatus;

Figure 4 is a horizontal section showing the floor of a modified form ofoven; and

Figure 5 is a longitudinal section of the oven of Figure 4.

In the drawings, referring first to Figures 1 to 3, the oven chamber 114is provided with the floor 12, preferably formed of refractorymaterial, and which is heated from below by combustion taking place inthe ues 13. These flues 13 may be heated' by gas or liquid fuelintroduced through nozzlesv 14, controlledv by valves 15. These nozzlesare provided at both ends of the flues 13.

'Ihe passage 16 serves to introduce the air which passesl up through theheating flues 17 andthrough passage 18 into the combustion flues 13. Thecenter of the construction is provided with the passages 19 for carrying01T the products of combustion which pass to the offtake passage 21.

As shown in Figure 3, the products of combustion may pass olf throughthe offtake header 22 and through the recuperator or heat transferapparatus 23, for the purpose of preheating the incoming oil or residue.The products of combustion may also pass through the v recuperator orsimilar heat interchange apparatus 24 for preheating incoming air orsteam, and from the apparatus 24 through passage25 to the stack 26.

The upper portion of the oven chamber 11 is closed by the housing 27which is provided with a'dome 28 and an offtake passage 29 which servesto carry on the volatilized constituents of the material being treated.The material being treated is introduced through the nozzles 30, theheavy liquid hydrocarbon being introduced through the pipes 31controlled by valves 32. These pipes 31 lead from the oil header 33. Theair or steam under pressure may be introduced into the nozzles 30through pipes 34, the supply being controlled by valves 35. An air orsteam header 36 is provided connecting the several pipes 34. As shown inFigure 3, the oil valves 32 are connected by pipes 33 with the oil orresidue preheating apparatus 23 into which the oil is introduced throughpipe 38. Similarly, the compressed air or steam headers 36 are connectedwith the air heater or steam superheater 24. The air or steam may beintroduced into the heater 24 through pipe 40, which' may be connectedto any suitable apparatus for providing a supply of compressed air orsteam.

The pipes 41 connect the offtake passage 22 with the nozzles 42, thepipes being controlled by valves 43. The nozzles 42 are shown asextending into the cover of the chamber 11. These nozzles or ports 42surround the smaller nozzles` 30, which may act as inspirators to drawthe ilue gases from the passages 41 into the oven chamber 11 should thepressure in the offtake passage 22 not be suicient to deliver thedesired amount of flue gases, or should the suction in the chamber 11 beinsufficient to draw in the desired amount of flue gases.

Non-oxidizing gases may be introduced through pipes 44 controlled byvalves 45 to equalize the temperature of the incoming gases from theflues 21, or gases similar to the noncondensible gases produced by theoperation of the process may be introduced `through these pipes undersufficient pressure to inspirate the flue gases into the chamber whenthis is necessary.

Referring now vto the form of construction shown in Figures 4 and 5, thechamber 50 is provided with the oor 51 having a series of openings 52which communicate with the longitudinally extending ues 53 located belowthe floor 51.

In the form of construction shown, these i'lues` extend the full lengthofthe oven and alternate ues are provided at opposite ends of the ovenwith burners 54 for the introduction of combustible gas or liquid fuel.'Ihese burners 54 are fed with fuel through headers 55. The airnecessary for combustion is introduced from air headers 56 into lowerpassages 57 wherein the air is some what preheated by radiation from thesuperposed combustion flues. From the lower flues 57 the air passesthrough openings 58 and 59 into the combustion flues 53.

The top of the chamber 50 is provided withthe offtake 60 for the gaseousproducts of the process. Each end of the chamber 50 is provided with thecross shaft 61 carrying sprocket wheels or the equivalent 62. One orboth of Athese wheels 62 may be power driven and the continuous convveyor 63 is carried over the two wheels 62. This conveyor consists of aseries of interlinked pans V64 which have their open side upperward onthe since partial combustion is the essential feature,

this gas may be pure oxygen or any gas containing a sufficientpercentage of oxygen for the purposeintended. If oxygen is used alone,it will be V apparent that the gaseous products of the process will beof higher B. t.- u. value than when air is used, as the products will besubstantially ni= trogen free. f

We have found by long experimentation that if the residue is used justas it comes from the vaporizer of the usual oil treatment apparatus, ata temperature of approximately 700 F. the process may be carried on toadvantage without additional preheating of the residue before itisintroduced into the chamber. The heat interchanger 23 for the preheatingof the oil or residue is of particular importance where the residue isnot received at relatively high temperatures.

It will be understood that this' invention is applicable to thetreatment of residues of such a character that they are solid at normaltemperatures, and in this case, if cold residue is treated it will benecessary to preheat it suiilciently to bring it to a liquid statebefore passing it through the heat interchange apparatus 23. Where theresidue is introduced with an oxygen-containing gas according to onenner of carrying out our invention, it is found desrable, though notabsolutely essential, to preheat the gas prior to its admixture with theresidue. This preheating reduces the amount of gas and the amount ofcombustion necessary to produce the desired coking temperature in thecoking chamber.

For certain purposes and with certain types of heavy hydrocarbons it maybe undesirable to allow partial combustion of the hydrocarbon itself.Combustion may render some or all of the condensible volatilesvundesirable for certain purposes.

Our method may be carried out without material combustion of thehydrocarbon being treated, by the use of the pipes 4l and nozzles 42. Inthis manner of carrying out our method the heavy hydrocarbon may beintroduced alone or maybe sprayed in with steam or any non-oxidizinggas. through nozzles 30.

The internal heat may then be had from the nozzles or ports 42, whichreceive products of combustion through pipes 41. These products ofcombustion may be used merely for their sensible heat. These gases willbe highly heated and will normally be above a coking temperature. Ifadditional heat is desired, these gases may be only partly burned in theues below the floor and additional air for a secondary combustion may beintroduced through the pipes 34 controlled by valves 35. If the fluegases are too hot, their temperature may be reduced by supplying coolergases through pipes 44, controlled by valves 45. Gases .under pressuremay be supplied through these pipes 44 to draw the flue gases throughthe ports 42.

While the heating of the floor of the oven is not absolutely essentialin these methods of operation, it is found desirable to maintain thisfloor at substantially a coking temperature at the time of introductionof the first portion of the material being treated. This avoids chillingthe material and starts the process without delay. After a layer of cokehas been formed on the floor, the process may be interrupted and thecoke pushed vor drawn from the chamber. The coke formed may, however, becontinuously removed by a suitable scraping device so that the processmay be continuous.

The nozzles 30 should be such as to bring about an intimate mixturebetween the residue and oxygen or oxygen-containing gas when this isused, so that the combustion takes place rapidly and uniformly withoutoverheating portions of the material. The amount of oxygen used when theoil is introduced at comparatively high temperatures may be only a verysmall percentage of the oxygen which would be necessary for completecombustion. The actual combustion may be, therefore, very slight and canbe held at such a point that the oils drawn oi have substantially noobjectionable oxidation odors. While the material is sprayed into theoven, it has been found in operation that the residue is not depositedas coke dust, but forms a definite solid layer of' coke which is firm instructure and suitable for commercial purposes.

The volatile'constituenis of the material being treated are drawn offfrom the upper portion of the chamber through the dome 28 and passage 29and may be taken to any usual apparatus (not shown) for the treatment ofsuch gases and vapors. For example, they may be passed throughfractionaiing towers where `the dierent fractions may be condensed andthe fixed gases remaining will be found to have a very high B. t. u.value. For example, with cold air and warm oil, a gas has been producedwhich runs from 350 to 400 B. t. u.s per cubic foot. On the other hand,where the air is preheated and the oil is at a higher temperature, it isunnecessary to introduce so much air for voxidation and consequently thenitrogen content of the gas is lower and a gas of from 500 to 600 B.y t.u.s or even higher may be produced. Y

In carrying out our method of operation with the form of apparatus shownin Figures 4 and 5, it willbe understood that the chamber 50 will beheated both by radiated heat from the oor 51 and by the gaseous productsof combustion which will pass through openings 52 up against the underside of the pans and through the chamber 50, and pass oi through oitake60 with the gases and vapors formed in the process. The material to betreated is fed into the pans 64 through ythe nozzles 65.

It will be understood that the movement of the conveyor may beintermittent or continuous,-

as desired, In one form of operation, for example, the conveyor might begiven a step by step movement with a predetermined amount of thematerial to be treated fed into each pan as it is halted under thatparticular nozzle. The spacing between nozzles 65 might be sufficient sothat the time of movement between the nozzles would permit the materialdeposited by one nozzle to be coked before material is deposited in thesame pan by the next succeeding nozzle. Thepans 64 may be so overlappedat their adjacent edges that the movement of the pan conveyors may becontinuous without loss of material between pans and may be at such arate as to cause the pan to secure the desired amount of material beloweach nozzle which may discharge continuously.

The alternate flues 53 are ilred from opposite ends so as to give asubstantially uniform heating to the oor and to give a substantiallyuniform discharge of hot gases through the openings 52 in the oor. Theopenings 52 are located toward the far end of each ue 53, or the enddistant from the nozzle in that ilue.

In the form of construction shown in Figures .1 and 3, a flat oor, isused while in the form of Figures 4 and 5, pans are used whichmay havesubstantially flat bottoms or surfaces for receiving the material. Otherforms of flat or approximately flat surfaces may be used where theyaccomplish the desired result. This may include large types ofcylindrical stills which are placed horizontally, so that the bottomsurface inside the stills may be somewhat curved we contemplate suchchanges and modications as come within the spirit and scope of theappended claims.

We claim:

1. The method of treatment of heavy hydrocarbons in liquid form, whichcomprises spraying the hydrocarbon together with an oxygencontaining gasinto a'closed chamber, thev chamber being at approximately atmosphericpressure, the temperatures of the liquid and oxygen being such as tocause partial combustion of the liquid, thus raising the temperature ofthe liquid to such a point as to drive oi the volatile portions of theliquid and progressively deposit a solid carbonaceous residue upon thefloor of the chamber, the residue being in the form of coke, externallyheating the iioor of the chamber to approximately a coking temperature,and periodically interrupting the introduction of the hydrocarbons andwithdrawing the formed layer of coke.

2. The method of treatment of heavy hydrocarbons in liquid form, whichcomprises continuously introducing the liquid into a. closed chamber atapproximately atmospheric pressure, depositing the liquid in asubstantially horizontal layer therein, -introducing heated gases intothe chamber, the gases being at substantially a. coking'temperature,thus raising the temperature of the liquid to such a point as to driveoff volatile portions of the liquid and progressively deposit a solidcarbonaceous residue upon the iloor of the chamber, the residue being inthe form of coke, externally heating the floor of the chamber toapproximately a coking temperature to assist the formation of the cokethereon, and

periodically interrupting the introduction of the liquid hydrocarbonsand withdrawing the formed layer of coke.

3. The method of treatment of heavy hydrocarbons in liquid form, whichcomprises continuously introducing the liquid into a closed chamandgases being at such temperatures and the 150 oxygen being in suchquantity as to cause partial combustion of the liquid to raise thetemperature of the remainder of the liquid to such a point as -to driveoff volatile portions of the liquid and progressively deposit a solidcarbonaceous residue upon the oor of the chamber, the residue being inthe form of coke, externally heating the oor of the chamber to approxi-

